Model-independent analysis of varvec{b rightarrow d} processes

Abstract

We perform a model-independent analysis of |Delta b|=|Delta d|=1 processes to test the standard model and probe flavor patterns of new physics. Constraints on Wilson coefficients are obtained from global fits to B^+ rightarrow pi ^+ ,mu ^+mu ^-, B^0_srightarrow bar{K}^{*0}, mu ^+mu ^-, B^0rightarrow mu ^+mu ^-, and radiative B rightarrow X_d ,gamma decays data. The fits are consistent with the standard model but leave sizable room for new physics. Besides higher-statistics measurements and more data in theory-friendly bins of the dilepton mass, further complementary observables such as angular distributions of B_s^0 rightarrow bar{K}^{*0},ell ^+ ell ^-, B rightarrow rho ,ell ^+ ell ^- or the baryonic modes Xi _b rightarrow Sigma ,ell ^+ ell ^-, Omega _b^- rightarrow Xi ^- , ell ^+ ell ^- are necessary to resolve the significant degeneracy in the fit for the semileptonic four-fermion operators. Assuming minimal quark flavor violation, the b rightarrow s global fit implies tight constraints on the b rightarrow d couplings, and hence allows to test this paradigm with improved data. Another benefit from |Delta b|=|Delta d|=1 processes is to shed light on the B-anomalies in |Delta b|=|Delta s|=1 modes from a new angle. Specifically, studies of lepton flavor-specific and dineutrino modes are informative on the lepton flavor structure. Rare b rightarrow d , ell ell , nu bar{nu } decays can be studied at high luminosity flavor facilities LHCb, Belle II, and a future Z-factory.